1. Field of the Invention
The present invention relates to a processing system, a processing method and a computer program, each adapted for processing an object or objects to be processed, such as semiconductor wafers, and in particular relates to the processing system, the processing method and the computer program, of a batch type, adapted for collectively processing multiple sheets of objects to be processed.
2. Background Art
In a process of manufacturing semiconductor devices, the batch-type processing system adapted for collectively providing a process, for example, a film-forming process, an oxidizing process, a diffusing process and the like, to the multiple sheets of objects, such as semiconductor wafers or the like, is employed. With such a batch-type processing system, the semiconductor wafers can be performed efficiently. However, it is considerably difficult to secure uniformity of the process for the multiple sheets of semiconductor wafers.
As a technique for solving such a problem, for example, in Patent Document 1, a method for enhancing a yield of the semiconductor devices has been proposed. Namely, in this method, three or more gas injectors, each adapted for introducing a gas, into a diffusion furnace from an upper portion, an intermediate portion and a lower portion thereof, are provided, in order to make a supply amount of the gas uniform by independently controlling their flow rates.
Additionally, Patent Document 2 teaches a heating method, which can perform a significantly uniform process while changing positions for supplying a processing gas or gasses, at least between a central portion and a peripheral portion in a face of each object to be processed, by changing a flow rate of a carrier gas during a heating process.
Furthermore, in Patent Document 3, another method has been proposed, in which a relationship between the flow rate of the processing gas or gasses supplied from a plurality of pipes and a growing speed of a film on each substrate is first estimated, and a film forming process is then performed with the flow rate of the processing gas or gasses supplied from the plurality of pipes being controlled.
Patent Document 1: TOKUKAIHEI No. 11-121389, KOHO
Patent Document 2: TOKKYO No. 3081969, KOHO
Patent Document 3: TOKUKAI No. 2003-166066, KOHO
In the batch-type processing system, although it can provide an appropriate process at a start of operation, it may tend to perform different processes from that planned at the start of operation, through many repetitions of processing operation or by changes of external factors and the like. For instance, in the case of a film-forming process for the semiconductor wafers, even though it can form a film having an appropriate film thickness on each semiconductor wafer at the start of operation, the thickness of the film formed on the semiconductor wafer sometimes changes through repetitions of the film forming process. This might be caused by the supply amount of the gasses that cannot adequately correspond to change over time of the processing furnace of the processing system and/or to change of the external environment. To address such an event, an operator of the processing system must currently control the flow rate of each gas, by experience and/or intuition, in order to secure the uniformity of the thickness of the film formed on each wafer surface. Thus, it is substantially difficult to secure the uniformity of the film thickness in the film forming process. Therefore, there is a need for the processing system and the processing method, by which even the operator having less or no experience and information on the processing system and the process itself can readily control the gas flow rate.